A standard door latch has a locking element displaceable between a locked position and an unlocked position and a bowden cable having one end connected to the element and an opposite end. Normally the locking element serves in an unlocked position to couple an actuating lever to a pawl. The pawl in turn serves to retain a latching fork that can engage around a bolt to hold the door closed. Thus in the unlocked position actuation of the actuating lever, for instance by a door handle, serves to pull the pawl off the fork and release the bolt, unlatching the door. In the locked position the locking element decouples the actuating lever from the pawl so that, even if it is actuated, the door stays latched.
The inside locking mechanism is typically a lever connected through the bowden to the locking element and actuating lever. When the element is in the unlocked position, operation of the inside actuating assembly, typically by pivoting a handle thereof, operates the actuation lever to unlatch the door.
In order to render the inside actuating assembly ineffective in the locked position of the locking element as defined in commonly owned U.S. Pat. No. 5,681,068 there is a link mechanism between two parts of the actuating assembly. In the unlocked position the link mechanism couples the two parts together and in the unlocked position it decouples them, much like the way it couples and decouples the actuating lever and pawl in the latch itself.
While such a system is fairly effective, it represents extra moving parts that can fail and that raise the cost of the actuating assembly.